The present invention relates to a gravity actuated gripper for gripping loads or molds containing radioactive substances, and more particularly to a gripper of the type having concentrically disposed lockable shells which are displaceable with respect to one another between two positions, the inner shell having recesses and the outer shell having a groove; balls which are seated in the recesses of the inner shell and which can be pressed partially into the interior of the inner shell by the outer shell, and thus into locking relationship with the load or mold, or which can lie completely within the recesses or in the groove in the outer shell; and a mechanical control device between the shells to fix the positions thereof, the mechanical control device being operated by raising and lowering the gripper.
Such a gripper is known from German Auslegeschrift No. 1,284,526. This known gripper is controlled and locked in its two end positions, "Locked" and "Release", by means of a ball which rotates in a groove disposed between the two sleeves. It is relatively complicated to manufacture a gripper which is controlled by means of such a groove, and moreover the gripper is unreliable in operation since corrosion may impede the mobility of the ball.